Cancer is caused by mutations (alterations) in oncogenes and tumor suppressor genes. Much of what we know about the function of cancer-causing genes comes from studies of genetic model organisms like fruit flies and soil nematodes. This project focuses on the Myb oncoprotein and its interactions with a four-protein tumor suppressor complex called the MuvB core. The fruit fly is an excellent model for these studies because it has only one Myb gene, whereas vertebrate animals including humans have three related Myb genes. In particular, the human B-Myb gene that is associated with poor prognosis in human breast cancer is structurally similar to and can functionally replace the Myb gene of fruit flies. Previous work has shown that the MuvB tumor suppressor proteins prevent the expression of genes that promote cell division. The Myb protein directly interacts with the MuvB proteins, thereby permitting the expression of the genes that MuvB inhibits. A major goal of this proposal is to understand in molecular detail the mechanism by which Myb and MuvB regulate gene expression. The tools of genetics, biochemistry, and cell biology will be used to identify the changes in chromatin (DNA and associated proteins) that occur in the presence of Myb and MuvB. Another major goal is to understand exactly how the Myb and MuvB proteins interact with and regulate one another. A relatively small portion of the Myb protein is sufficient to interact with the MuvB proteins and inhibit their function. A better understanding of the precise structures that mediate this interaction may lead to the development of new small molecules that will be useful in the treatment of breast cancers with increased levels of B-Myb.

Public Health Relevance

Mutations (alterations) in normal genes cause human cancer. The genes being studied in this project are known to be mutated in human breast cancer, leukemia, and lymphoma. The goal of the project is to understand how the proteins produced by these genes control cell division and cell identity, two properties of cells that are deranged in cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA128836-07
Application #
8640110
Study Section
Molecular Genetics B Study Section (MGB)
Program Officer
Spalholz, Barbara A
Project Start
2007-09-01
Project End
2017-03-31
Budget Start
2014-04-01
Budget End
2015-03-31
Support Year
7
Fiscal Year
2014
Total Cost
$266,636
Indirect Cost
$96,804
Name
Stanford University
Department
Pathology
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
DeBruhl, Heather; Wen, Hong; Lipsick, Joseph S (2013) The complex containing Drosophila Myb and RB/E2F2 regulates cytokinesis in a histone H2Av-dependent manner. Mol Cell Biol 33:1809-18
Davidson, Colin J; Guthrie, Erin E; Lipsick, Joseph S (2013) Duplication and maintenance of the Myb genes of vertebrate animals. Biol Open 2:101-10
West, Robert B; Kong, Christina; Clarke, Nicole et al. (2011) MYB expression and translocation in adenoid cystic carcinomas and other salivary gland tumors with clinicopathologic correlation. Am J Surg Pathol 35:92-9
Ouyang, Yingshi; Petritsch, Claudia; Wen, Hong et al. (2011) Dronc caspase exerts a non-apoptotic function to restrain phospho-Numb-induced ectopic neuroblast formation in Drosophila. Development 138:2185-96
Andrejka, Laura; Wen, Hong; Ashton, Jonathan et al. (2011) Animal-specific C-terminal domain links myeloblastosis oncoprotein (Myb) to an ancient repressor complex. Proc Natl Acad Sci U S A 108:17438-43
Wen, Hong; Andrejka, Laura; Ashton, Jonathan et al. (2008) Epigenetic regulation of gene expression by Drosophila Myb and E2F2-RBF via the Myb-MuvB/dREAM complex. Genes Dev 22:601-14